#!/usr/bin/env node 
const cp=require('child_process');
console.log(`I am Father,PID:${process.pid}`);
const cat=cp.spawn('cat',['data.txt']);
const sort =cp.spawn('sort');
const uniq=cp.spawn('uniq');
cat stdout.pipe(sort.stdin);
sort.stdout.pipe(uniq.stdin);
unqi.stdout.pipe(process.stdout);

